The present invention relates to remote seal systems for use with industrial process pressure transmitters. More specifically, the present invention relates to such remote seal systems used in extreme temperature environments.
Industrial process control systems are used to monitor and control industrial processes used to produce or transfer fluids or the like. In such systems, it is typically important to measure “process variables” such as temperatures, pressures, flow rates, and others. Process control transmitters are used to measure such process variables and transmit information related to the measured process variable back to a central location such as a central control room.
One type of process variable transmitter is a pressure transmitter which measures pressure of a process fluid and provides an output related to the measured pressure. This output may be a pressure, a flow rate, a level of a process fluid, or other process variable. The transmitter is configured to transmit information related to the measured pressure back to a central control room. The transmission is typically over a two wire process control loop, however, other communication techniques may be used, including wireless techniques.
The pressure must be coupled to a process variable transmitter through some type of a process coupling. For example, the process fluid can comprise a component used in an industrial process such as natural gas, oil, etc. In certain process pressure measurement applications, the pressure transmitter is located remotely relative to a pressurized process fluid, and pressure is physically conveyed from the process fluid to the pressure transmitter through a fluid link using a device called a remote seal.
In specific applications where great temperature differences between ambient and process temperatures are encountered in the environment surrounding the remote seals, the remote seals may perform poorly (or are not configurable at all for these applications) and this leads to potential inaccuracies in the measured pressure and other problems. There is a need to improve remote seals to better withstand great temperature differences.